Facebook snapped up Instagram, the photo-sharing app, in April. They paid $1 billion in cash and stock, which was very, very friendly of them, but also very prescient. Facebook + Instagram = a nice app/brand synergy of the experience of sharing photos and interests.
At the time, Facebook founder, Mark Zuckerberg, said that the company would be building on Instagram's strengths and features and growing the app independently rather than "just trying to integrate everything into Facebook." Facebook indicated that they intended on keeping features within the app that allowed photos to be published on other social networks, and the ability to have followers and to follow people who are not necessarily Facebook friends.